Maximum likelihood (ML) tree of Alx proteins.

The tree was constructed using conserved amino acid sequences. The numbers on the nodes indicate the bootstrap values (1,000 pseudoreplicates). Values greater than 50% are shown. Ak: Amphipholis kochii (brittle star); Ap: Asterina pectinifera (starfish); Bf: Branchiostoma floridae (amphioxus); Dr: Dario rerio (zebrafish); Hl: Holothuria leucospilota (sea cucumber); Hp: Hemicentrotus pulcherrimus (sea urchin); Hs Homo sapiens (Human); Mr: Metacrinus rotundus (sea lily); Pm: Patiria (Asterina) miniata (starfish); Sk: Saccoglossus kowalevskii (acorn worm); Sp: Strongylocentrotus purpuratus (sea urchin).